In U.S. Pat. No. 5,586,844 to Nyman, there is illustrated and described a cutting insert holder with a clamping wedge for releasably clamping a cutting insert with an obtuse insert mounting corner in a symmetrical seating arrangement whereupon the cutting insert assumes a predetermined clamping position.
In FIGS. 1, 2 and 3 corresponding, respectively, to FIGS. 1, 3 and 5 of U.S. Pat. No. 5,586,844 to Nyman, but with different reference numerals, a cutting tool comprises a cutting insert holder 10 with a clamping wedge 12 that releasably clamps a cutting insert 14 in a symmetrical seating arrangement whereupon the cutting insert 14 assumes a predetermined clamping position. The cutting insert 14 has a throughbore 16, obtuse insert mounting corners 18 and non-obtuse cutting corners 20.
The cutting insert holder 10 has a holder body 22 with a top surface 24 and a bottom surface 26 and a recessed forward end portion 28 in the top surface 24 which defines an insert site. The insert site having an inclined wedge supporting surface 30 extending downwardly and forwardly from the top surface 24 toward a base surface 32 of the insert site. The cutting insert 14 is located at the insert site and is supported by a shim 34 positioned on the base surface 32. A generally upstanding rigidly mounted locking pin 36 is located in a bore 38 in the holder body 22 which opens out into the base 32. The locking pin 36 passes through a hole 40 in the shim 34 with a head portion 42 thereof located in the insert's throughbore 16. The clamping wedge 12 is located in recessed leading portion 28 wedged between the supporting surface 30 and the cutting insert 14. On the underside of the clamping wedge 12 is an insert receiving pocket 44 having an insert receiving corner 46 for receiving the cutting insert's mounting corner 18. The insert receiving corner is formed at the intersection of two planes passing through a pair of spaced-apart lower protrusions 48. The angle θ of the insert receiving corner is substantially equal in magnitude to the insert's mounting corner angle Φ. The clamping wedge 12 is upwardly biased by a spiral shaped spring 50 received in a counterbore 52 of a screw threaded clamping bore 54 in which a clamping screw 56 is threadingly received for slidingly urging the clamping wedge 12 down the wedge supporting surface 30 towards the base surface 32. In a top view of the cutting insert holder 10, the insert receiving pocket 44 is disposed relative to the wedge supporting surface 30 such that a normal 58 to the latter passing through a center 60 of the locking pin 36 bisects the insert receiving corner 46 and coincides with the cutting insert's diagonal 62 passing through the operative insert mounting corner 18′ and the operative cutting corner 20′, thereby rendering the symmetrical seating arrangement for the cutting insert 14.
However, a symmetrical seating arrangement adapted for a cutting insert with a non-obtuse insert mounting corner would not consistently clamp the cutting insert in a predetermined clamping position. Furthermore, it is not possible to use the above described cutting insert holder to releasably clamp both a cutting insert with an obtuse insert mounting corner and a cutting insert with a non-obtuse insert mounting corner.
It is an object of the present invention to provide a cutting insert holder with a clamping wedge for releasably clamping a cutting insert with a non-obtuse insert mounting corner in a predetermined clamping position.
It is a further object of the present invention to provide a cutting insert holder with a clamping wedge for releasably clamping both a cutting insert with an obtuse insert mounting corner and a cutting insert with a non-obtuse insert mounting corner.